Need help with a Bash Script

cmfarley19 · 08-05-2008, 09:52 AM

I've been having trouble with my ISP (Comcast) recently going up and down many times a day for many minutes a day.

I wrote a little script to go out to google every 5 minutes and it logs every time the connection is down. It will then log the next time the connection is back up.

Code:

     1  #!/bin/bash
     2  #       echo any arguments
     3
     4  DAT_FILE="/var/log/scripts/inetstate.dat"
     5  LOG_FILE="/home/cmfarley/connected.log"
     6  echo $1
     7
     8  # Get the date and time in spreadsheet friendly format
     9  DATE=$(date +%D' '%T)
    10
    11  # Try to connect.  If successful $CON="Google", else empty
    12  CON=$(lynx -dump -connect_timeout=10 google.com|grep -i Lucky|cut -d ' ' -f5)
    13
    14  # Get the last entry in the log
    15  TEMP=$( tail -1 $LOG_FILE |cut --complement -d ',' -f1|cut -d ' ' -f2)
    16
    17  # if an argurment (DEBUG) echo $TEMP
    18  if [ $1 ]
    19          then
    20          echo $TEMP
    21          echo $LOG_FILE
    22          VAR=`echo $1`
    23          echo $VAR
    24  else
    25          VAR="XXX"
    26  fi
    27   
    28  if [ $VAR == "-date" ]
    29          then
    30          date +%D  >> $LOG_FILE
    31  else
    32
    33          #if $CONNECT is empty...
    34          if [ -z $CON ]
    35                  then
    36                  echo "Not Connected" > $DAT_FILE 
    37                  # if $TEMP !empty, last attemp was connected, so log the disconnect
    38                  # else the last attempt was disconnected so do nothing
    39                  if [ $TEMP ]
    40                          then
    41                          echo "$DATE, " >> $LOG_FILE 
    42                  fi
    43
    44          else
    45                  echo "Connected to $CON" > $DAT_FILE 
    46                  # if $TEMP is empty, last attemp was !connected, so log the connection
    47                  # else the last attempt was connected so do nothing
    48                  if [ -z $TEMP ]
    49                           then
    50                           echo "$DATE" >> $LOG_FILE 
    51                  fi
    52
    53          fi
    54  fi      # -date

The output of the log file looks like this:

Code:

DOWN, UP
07/29/08
07/29/08 19:25:01, 
07/29/08 19:30:01
07/29/08 21:50:01, 
07/29/08 21:55:01
07/30/08
07/30/08 14:05:01, 
07/30/08 14:10:01
07/30/08 18:40:01, 
07/30/08 18:50:01
07/31/08
07/31/08 21:50:01, 
07/31/08 21:55:01
08/01/08
08/01/08 05:20:01, 
08/01/08 05:25:01
08/01/08 10:00:01, 
08/01/08 10:10:01
08/01/08 10:15:01, 
08/01/08 10:20:01
08/01/08 11:30:01, 
08/01/08 11:35:01
08/01/08 11:40:01, 
08/01/08 11:45:01
08/02/08
08/02/08 01:50:01, 
08/02/08 01:55:01
08/02/08 02:00:01, 
08/02/08 02:05:02
08/02/08 17:45:01, 
08/02/08 17:50:01
08/02/08 17:55:01, 
08/02/08 18:00:01
08/02/08 19:20:01, 
08/02/08 19:25:01
08/03/08
08/04/08
08/04/08 00:20:01, 
08/04/08 00:25:01
08/04/08 00:30:01, 
08/04/08 00:50:01
08/04/08 04:25:01, 
08/04/08 04:30:01
08/04/08 20:20:01, 
08/04/08 20:25:01
08/05/08
08/05/08 10:30:01, 
08/05/08 10:35:01

Line 41 outputs the down time stamp and line 50 outputs the up time stamp. What I want is the up time stamp to be on the same line as the down time stamp so they are in pairs.
Kind of like this:

Code:

...
08/04/08
08/04/08 00:20:01, 08/04/08 00:25:01
08/04/08 00:30:01, 08/04/08 00:50:01
08/04/08 04:25:01, 08/04/08 04:30:01
08/04/08 20:20:01, 08/04/08 20:25:01
08/05/08
08/05/08 10:30:01, 08/05/08 10:35:01

My grep, sed, and awk skills are little rusty.
Anybody have any suggestions?

Thanks,

Chris

Kenhelm · 08-05-2008, 11:26 AM

This joins the next line to the end of a line ending in ', '
i.e. a line ending in <comma><space>
(It assumes that the next line does not also end in ', ')

Code:

sed '/, $/N; s/\n//' infile > outfile

cmfarley19 · 08-05-2008, 12:12 PM

That does the trick for post processing the file.
I'll need to modify that to work on the fly inside of my script so would you mind explaining a couple elements of that command?
What is the "$/N;"?
Does that line "read"
- Find a comma space at the end of a line "/, $/"
- Append the next line (N

- Replace the next line with nothing.

Just a guess?

Kenhelm · 08-05-2008, 02:06 PM

'/, $/' Matches any line ending in ', '
'N' Means append the next line separated from the matched line by a newline \n.
's/\n//' Means remove the \n thereby turning two lines into one.

To do it from within the script try modifying line 41 to:-

Code:

echo -n "$DATE, " >> $LOG_FILE

With 'echo -n' the newline is suppressed.

cmfarley19 · 08-05-2008, 02:17 PM

Ahh...

Thanks.

Chris